Quantum fluctuations and coherence in high-precision single-electron capture

Abstract

The phase of a single quantum state is undefined unless the history of its creation provides a reference point. Thus quantum interference may seem hardly relevant for the design of deterministic single-electron sources which strive to isolate individual charge carriers quickly and completely. We provide a counterexample by analyzing the non-adiabatic separation of a localized quantum state from a Fermi sea due to a closing tunnel barrier. We identify the relevant energy scales and suggest ways to separate the contributions of quantum non-adiabatic excitation and backtunneling to the rare non-capture events. In the optimal regime of balanced decay and non-adiabaticity, our simple electron trap turns into a single-lead Landau-Zener-backtunneling interferometer, revealing the dynamical phase accumulated between the particle capture and leakage. The predicted "quantum beats in backtunneling" may turn the error of a single-electron source into a valuable signal revealing essentially non-adiabatic energy scales of a dynamic quantum dot.

7 pages, supplementary info in 3 appendices, final PRL version

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Cited by in corpus (7)

• Counting statistics for electron capture in a dynamic quantum dot
• Evidence for universality of tunable-barrier electron pumps
• Single-electron source: Adiabatic versus non-adiabatic emission
• Ultrafast Emission and Detection of a Single-Electron Gaussian Wave Packet: A Theoretical Study
• Landau-Zener-Stueckelberg physics with a singular continuum of states
• Ultrastable low-noise current amplifier
• Controlling the error mechanism in a tunable-barrier non-adiabatic charge pump by dynamic gate compensation